Fixed analyze issues

packages/container/angel_container/lib/src/container.dart

@@ -217,7 +217,7 @@ class Container {
     if (_namedSingletons.containsKey(name)) {
       return _namedSingletons[name] as T;
     } else if (_parent != null) {
-      return _parent!.findByName<T>(name);
+      return _parent.findByName<T>(name);
     } else {
       throw StateError(
           'This container does not have a singleton named "$name".');

packages/route/lib/src/route.dart

@@ -61,7 +61,7 @@ class Route<T> {
     var i = 0;
 
     if (_routeDefinition != null) {
-      for (var seg in _routeDefinition!.segments) {
+      for (var seg in _routeDefinition.segments) {
         if (i++ > 0) b.write('/');
         if (seg is ConstantSegment) {
           b.write(seg.text);

packages/user_agent/angel_user_agent/example/example.dart

@@ -6,6 +6,7 @@ import 'package:angel3_framework/http.dart';
 
 void main() async {
   var app = Angel();
+  // ignore: unused_local_variable
   var http = AngelHttp(app);
 
   //TODO: To be reviewed